firefairy

My SIL and I went through some tough times to. After 11 years we are just finally starting to see eye to eye and get a long.
You need to except her for who she is. She is crazy. Maybe a little jealous.. maybe downright rude... but that is who she is. You need to agree to disagree. You will not always see eye to eye with her.
The biggest problem is that the problem with you and your SIL is tearing your husband away from his family. He may be ok with this now, but i'm sure it is eating at him slowly. Having our families in our lives and a part of our childrens lives is important.
All families have drama, fighting, and crazy people! It is what it is! But as crazy as they are, they are your inlaws.
The spray thing.. it is a little odd... no one will ever know her true intention by asking you if you wanted some. Maybe she was trying to be nice because she likes using the stuff or maybe she was trying to hurt your feelings. Maybe you took it the wrong way. I'm sure if she wasn't giving you other issues you would've been able to just laugh it off but because she was being indifferent a few days before you took it offensively.
Everyone is different. Everyone has quirks. Everyone has flaws! You don't need to be BFF with your SIL but you should try to not let the things she does get to you... learn how to just ignore that crazy things she does, so that you can have a casual relationship with her for the sake of your family.
That is just my opinion!!